Elevator safety device.



J. F. BEMIES.

ELEVATOR SAFETY DEVICE.

APPLIcAnoN FILED 01m31.191s.

l ,-QUUQ. Patented Nov. 28, 1916.

'burn smart raie carmen.

JAMES F. BEMIES, OF NEW YORK, N. Y., ASSIGNGR T0 OTS ELEVA'IOR COMPANY, OF JERSEY CITY, NEW JERSEY, .A CORPORATION 0F NEW JERSEY.

ELEVATOR SAFETY DEVICE.

T0 all whom t may concern Be it known that I, JAMES F. BEMrns', a. citizen of the United States, residing in New York, in the county of New York and State of New York, have invented a new anduseful Improvement inr Elevator Safety Devices, of which the following is a specification.

My invention relates to safety devices for elevators, and has for an object the provif sionv of a novel device of this character which is simple, practical, eflicient and certain in its operation and whichwill effect a gradual and smooth stop of an elevator car in time of emergency under all conditions.

Otherobjects of the invention will appear hereinafter, the novel combinations of elements being pointed out in the annexed claims.

In the accompanying drawings, Figure l represents a typical elevator system containing an embodiment of my invention; Fig. 2 is a detail plan view in part section of the safety plank Fig. 3 is an elevation view of the safety plank in part section.

Similar parts are designated by like ref erence characters in -allof the figures.

Broadly speaking, my invention belongs tothat class of elevator safety devices in which reversely threaded screws are used to move a pair of wedge clamps into frictional engagement with the car guide rails. ln this type of device as well as in other types, it is found that the retarding action tends to be too severe with a lightly loaded elevator car, due in part to the fact that the guide rails are always coated with grease. rlhe retarding action under these conditions does not take place to any appreciable degree unless and until the clamp jaws have first contacted metal to metal' with` the guide rails. In order that such may be the case, the jaws must first clamp the rails with sufficient pressure to cut through or burn out the grease on the rails, and as this pressure is necessarily great the retarding force is correspondingly great. Furthermore the rigid and unyielding `nature of the clalnp jaws and guide rails is conducive of excessive andfharsh pressure which further tends to prevent a smooth and gradual stoppage of the car under all load conditions. My invention overcomes these, as well as other un- Specicaton of Letters Patent.

Application led October 31, 1913.

Patented Nov. 28, i916.

Serial No. 798,395.

desirable features inherent in the present day safety devices, and for this reason marks a decided advance in the art to which my invention relates.

Referring to Fig. l of the drawings, l show an elevator car C and counterweight l which are suspended from the cable or cables R and adapted to be reciprocated by means of some power device such as an electric or hydraulic motor. A safety governor A isv located at the top of the hatchway and is driven by a governor cable l which is operatively connected normally to run with the ear. This operative connection comprises a releasing carrier 2 which allows a relative movement between the governor cable l and the car when the governor clamps B are operated by excessive car speed. A safety cable 3 is securely fastened to the governor cable l and is wrapped several times about the safety drum 5 carried by the safety plank G and its end is made fast thereto. A weighted tension sheave l lies in a bight in the governor cable 1 and maintains the same under a predetermined tension. The eounterweight'VV and car C are provided with guide rails as is customary with all elevators and while the counterweight guide rails are of standard construction, the car guide rails G depart from the usual practice in that they involve a novelty in construction containing several advantageous features. The guide rails G cooperate with the safety device carried by the car which device is designated in this figure by the reference numeral 6.

Referring to Figs. 2 and 3, it will he seen that the guide rails G are a radical departure from standard practice and are formed of steel of a cross sectional area and strength proportional to the maximum load the car will ever be called upon to handle, and in cross section similar in form to a goblet having turned in edges; that is to say each rail is formed of two eccentric circles so that the rail presents an inner circularl recess and an outer circular periphery, and having the usual flat base by which it is attached to the sides of the hatchway. The inner circular recess of the oppositely disposed guide rails each contains an eXpanding bushing or wedge member such as 7 and 7 preferably made of tool steel or other suitable material, adapted to spring or flex under pressure.

The wedge member 7 comprises a block of steel containing a vertical slot 8 extending through the greater part of the wedge member and terminating at a vertical hole 9. One end of this wedge member is enlarged and rounded off so as to form a. cylindrical head 10 which lies within the recess in the guide but normally not in contact therewith, as a small annular space is left between the two. lVithin the wedge member, and adjacent the upper and lower ends thereof, are tapered slots 19, 19, in which are arranged wedges 15, 15. To eaeh wedge 15 is secured a rod 14: both of which extend through the wedge member 7 and are securedr by a rocking connection to a yoke 16 which is guided by the blocks 21. The center of this yoke is pivoted to a screw 17 supported by a, brace 18 and threaded intothe safety drum 5, and the yoke acts as an equalizer in that it assures that the pressure of the screws will be equally divided between the wedges. rlhe wedge member 7 is carried in a vsupport 11 secured to the channel beams 13 forming the safety plank, and the outer ends 12` 12, of the support 11 are similar in shape to the outer periphery of the guide rail and slightly removed therefrom. The other end ef the safety plank is constructed similar to that just described, the only difference being that the screw 17l is reversely threaded to the screw 17.

The operation of the device is very easily understood and may be stated as follows: When vthe car` attains excessive speed, the governor balls fly outwardly and thereby .enable the governor clamps B to seize the governor cable 1 (see Fig. 1). The latter is arrested in its movement and the car, continuing in its flight, pulls loose from the governor cable at the releasing carrier 2. The relative movement now existing be- -tween the car and the governor cable causes the safety cable to be unwound fromthe safety drum 5 and the latter is rotated and draws the threaded screws 17 and 17 together regardless of whether the car be traveling up or down. As the screw 17 moves inwardly, the connected wedges 15, 15, likewise move inwardly and in so doing they expand the wedge member 7 into close frictional engagement with the inner recess of the guide rail and thus act to retard and finally stop the car.

It will be observed that as soon as the Wedge members 7 and 7 have been expandv ed so as te engage the guide rails, a further movement of the elevator car, attended by a further rotation of the safety drum 5, expands the wedge members with great force, which is yieldingly resisted by the spring action of the guide rails owing to the novel form of the latter, That is to say, as the wedge members expand, the guide rails being flexible will also expand and offer great resistance to the passage of the wedge members therethrough.

In order to limit the amount to which the guide rails may be expanded under pressure, I have provided the rigid members 12, 12, adjacent thereto, the arrangement being such that after a predetermined expansion of the lguide rails, the latter contact with the members 12, 12, and are restrained from further expansion. 1n this manner I obviate all danger of the guide rails being expanded beyond their elastic limit and from becoming set or permanently distorted in form and the stop of the car will be absolutely certain even though the latter be heavily overloaded.

The members 12, 12, may be used with the safety device or dispensed with altogether depending` largely upon load conditions. lVhen the load is heavy and the speed high .l prefer to use these members. but when both speed and load are moderate they may be left ofi", particularly waere the guide rails are heavily constructed. The members 12, 12 may be used to performl the functions of the usual lower car guides, and when so used the usual guide shoes for steadyinfr and guiding;- the lower part of the car may be left off, the. upper guide shoes as well as the members 12, 12 being` arranged to travel upon the outer periphery of the guide rails.

Bv reason of the novel construction of the guide rails 1 am assured of the absence of all grease and eil on the inner periphery of the guide rails which co-acts with the wedges, even though thel outer periphery be thickly covered with grease, so as to lubricate the guide shoes. Hence the retardation of the car due to the operation of the safety device will come into effect immediately the wedge members are expanded in contact with the guide rails without first having to remove or burn the lubricating matter from the rails as is now the case.

While I have shown and described one embodiment of my invention, I desire not to be limited to the precise construction and arrangement of parts herein set forth, since it is obvious that one skilled in the art could readily make changes in the arrangement herein disclosed without departing from the spirit and scope of the invention.

What I claim and desire to have protected by Letters Patent of the United States is 1. In an elevator safety device, the combination of a car, a hollow expansive guide rail, a bushing carried by the car and movable in the hollow guide rail, and means for expanding said bushing.

2. In an elevator safety device, the combination of a car, a hollow expansive guide rail, a bushing carried by the car and mov able in the hollow guide rail, and automatic means for expanding said bushing into frictional contact with the said guide rail to retard the car.

8. ln an elevator safety device, the combination of a car, a hollow guide rail, a bushing carried by the car and movable in the hollow guide rail, and means controlled by the speed of the car for expanding said bushing into frictional contact with the said guide rail to retard the car.

4. ln an elevator safety device, the combination of a car, a hollow expansive guide rail of substantially cylindrical form, and a device on the car adapted to be forced into frictional contact with said guide rail.

5. ln an elevator safety device, the combi- `nation of a car, a hollow expansive guide rail of substantially cylindrical form, and a device on the car freely movable within the hollow portion of said guide rail and adapted to be forced into frictional engagement therewith to retard the car.

6. In an elevator safety device, the combination with a hollow expansive guide rail of substantially cylindrical form, and means on the car for engaging the inner and outer periphery of said rail.

7. In an elevator safety device, the combination with a hollow guide rail of substantially cylindrical form, means carried by the car adapted to engage the inner periphery of said guide rail to retard the car, and additional means adapted to engage the outer periphery of said guide rail under the action of said first named means and thereby effect a further retardation of the car.

8. ln an elevator safety device, the combination of a car, a hollow guide rail therefor, an expanding bushing carried by the car and movable within the hollow portion of the guide rail, and a wedge adapted to effect the expansion of said bushing.

9. ln an elevator safety device, the combination of a car, a hollow guide rail therefor, an expanding bushing carried by the car and movable within the hollow portion of the guide rail, wedges adapted to effect the expansion of said bushing and means for operating said wedges with equal pressure.

l0. In an elevator safety device, the combination of a car, a hollow guide rail therefor, an expanding bushing carried by the car and movable within the hollow portion of the guide rail, wedges adapted to eifect the expansion of said bushing, a screw adapted to operate said wedges, and an equalizing device between said wedges and screws.

ll.v In an elevator safety device, the combination of a car, hollow guide rails therefor, expanding members on the car movable in the hollow guides, wedges adapted to effect the expansion of said members, oppositely threaded screws controlling said wedges, a drum threaded on said screws, and means for effecting a rotation of said drum and thereby setting up a frictional engagement between the guide rails and the eX- panding member to retard the car.

l2. ln an elevator safety device, the combination with a car, of a brake carried by the car, a yielding substantially cylindrical guide rail for the car, and means for effect ing the application of the brake to said rail to retard and stop the car.

ln testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

J AMES F. BEMIES.

Witnesses:

WALTER C. STRANG, JAMES G. BELHELL.

Uopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, 1D. C. 

